02156nas a2200241   450000500170000000800410001703500150005810000260007324500410009926000520014030000220019249000260021450001020024050200510034252012100039365000360160365000270163970000350166670000480170170000420174971000650179181000580185620260818170321.0301098s1983    th      r     000| 0eng d  a.b1047187x1 aBautista, Mendeluz B.10aNutrient release from lake sediments  aBangkok :bAsian Institute of Technology,c1983  a94 leaves :bill.1 aThesis ;vno. EV-83-5  aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science  aThesis (M.Sc.) - Asian Institute of Technology  aDiffusional fluxes ranging from 14-30 mg NH4/m2-d and 0.1-0.5 mg P04/m2-d  were computed for Laguna Lake sediments. Laboratory and in situ experimental  results ~ielded rates of release in the order of 5-8 mg TIN/m2-d and 0.5-0.8  mg DIP/m -d. On the other hand, nutrient budget calculations for TIN during  the 1973-1977 period showed slightly lower values, 4-5 mg TIN/m2-d, which are  believed to be overestimates since the larger component would be accounted  for by internal recycling of N in the water column. DIP budget calculations  revealed P uptake by the sediments instead of release over the four-year period  at rates of 0.8-1.0 mg DIP/m2-d. Based on these, Laguna Lake sediments would  not be major sources of nutrients and, as in the case of phosphorus, could  even serve as a nutrient sink.  The transport of N across the sediment-water.interface was not as predo-  minantly controlled by the concentration gradient between the two phases, as  was P flux. This indicates that the mechanism for P release involves mainly  equilibrium-controlled chemical_processes, which are less prevalent in N sedi-  ments enhanced TIN release while DIP release was inhibited under aerobic condi-  tions.   0aWaterxPurificationxFiltration 0aFilters and filtration0 aSamorn Muttamara,eChairperson0 aChongrak Polprasert,eExamination Committee1 aOmura, Tatsuo,eExamination Committee2 aUS-ASEAN Development Cooperation Program,eScholarship Donor2 aAsian Institute of Technology.tThesis ;vno. EV-83-5